The present invention relates to a method and to a device for setting the short circuit moment in electric motors, particularly in servomotors.
In connection with electric motors, particularly servomotors, it is usually required that the tolerance range of the adjustment or motor forces lies within very narrow limits. The short circuit moment, that is, the torque when the motor drive shaft is held immobile, is proportional to the actuation forces of the system equipped with the motor. However, in practice there exist a large number of power influencing tolerances of the individual components of an electric motor so that a large margin of error results for the short circuit moment in the conventional manufacturing and installation methods which is undesirable and also not permissible in many applications.
To obtain electric motors that have a narrower tolerance range, it has been the practice in the past to subject the motors to an appropriate test and to reject those displaying values outside of the tolerance range. However, this is a very expensive method and, in addition, the tolerance range cannot be made arbitrarily small if costs are to be kept within an economically justifiable range. Another known possibility to obtain a narrow tolerance range for the short circuit moment is the use of very high quality and high precision components. However, this way also leads to high costs.